Development and Validation of a Biopsy-Free Scoring System for Screening Myelodysplastic Syndrome (MDS) and Associated Diseases in Cytopenic Patients

Introduction

Myelodysplastic Syndromes (MDS) are a spectrum of clonal hematopoietic disorders characterized by peripheral blood cytopenia and increased risk of progression to acute myeloid leukemia (AML). Patients are often present with varying degrees of cytopenia and may not show overt symptoms, resulting in challenges in their diagnosis. The bone marrow study to identify dysplastic features is a gold standard for diagnosing MDS based on morphological criteria. However, this invasive procedure may not be necessary for patients whose cytopenia results from non-clonal diseases. This study aims to develop a non-invasive screening tool that integrates clinical data, laboratory parameters, and genetic analyses to assess the need for bone marrow biopsies in patients presenting with cytopenia.

Patients and Methods

This study involves both retrospective and prospective data collection from patients presenting with cytopenia at 4 University Hospitals in Thailand (King Chulalongkorn Memorial Hospital, Vachira Hospital, HRH Princess Maha Chakri Sirindhorn Medical Center, and Maharaj Nakorn Chiang Mai Hospital) from 2018 to 2023. Medical records were reviewed to extract essential diagnostic data for MDS and related conditions. Eligible participants were adults over the age of 18, presenting with anemia (hemoglobin levels < 13 g/dL for males, < 12 g/dL for females) or neutropenia (Absolute Neutrophil Count, ANC < 1.8x10⁹/L), or thrombocytopenia (platelet count < 150x10⁹/L). Known causes of cytopenia such as hematological disorders or other medical conditions were excluded. Gene mutation analysis was performed using the Ion Torrent™ Oncomine™ Myeloid Research Assay via Next Generation Sequencing (NGS), targeting a comprehensive panel of 40 genes relevant to myeloid neoplasms. Significant clinical mutations were defined as having a variant allele frequency (VAF) > 5%.

Results

The study included 285 participants; 210 diagnosed with MDS and related diseases: MDS 144, MDS/MPN 32, AML-MR 34 (MDS group), and 75 as non-MDS group. The average age at presentation was similar across both groups, with no significant gender differences. Patients in the MDS group showed more anemia (hb 8.7 vs. 10.2 g/dL; p<0.001) and neutropenia (1.8 vs. 1.9x10⁹/L; p=0.02) than the non-MDS group. A significantly higher number of patients with red cell distribution width (RDW)≥15% or harbored more than 2 mutations was observed in MDS group compared to non-MDS group (75% vs. 44%; p<0.001 and 46% vs. 2.7%; p<0.001). Most common gene mutations in the MDS group were TET2 (42%), SRSF2 (35%), ASXL1 (32%), RUNX1 (25%) and DNMT3A (22%), respectively.

A univariate analysis showed that anemia (hb<10 g/dL), neutropenia (ANC<1x10⁹/L), thrombocytopenia (platelet<100x10⁹/L), RDW≥15%, ≥2 mutations, 6 gene mutations (TET2, ASXL1, SRSF2, RUNX1, TP53, SF3B1), high-risk mutations and other risk mutations were significant predictors for MDS and related diseases. High-risk mutations included NRAS, NPM1, IDH2, SETBP1, CEBPA, JAK2, IDH1, FLT3 and KRAS, while other risk mutations included BCOR, U2AF1, STAG2, ZRSR2 and PTPN11. The significant thirteen factors from univariate analysis were incorporated into a multivariate logistic regression model, which was internally validated using a bootstrap sampling method with 1,000 replications, demonstrating good fit and predictive accuracy, evidenced by an area under the ROC curve of 0.86. For patients with a probability score of ≥45%, sensitivity was 90.47%, specificity was 42.67%, PPV was 81.5%, and LR+ was 1.58 for diagnosing MDS and related diseases. A practical web-based calculator for this scoring system can be accessed at (https://www.calconic.com/calculator-widgets/biopsy-freescore/668a812c88a6d3002a670f60?layouts=true).

Conclusion

Biopsy free score developed from integrating complete blood counts (CBC) and gene mutations helps predicting diagnosis of MDS and related diseases in patients present with cytopenia. For patients with a probability score < 45%, a bone marrow study may not be needed, with a recommended follow-up every 6–12 months. This comprehensive analysis provides a useful and non-invasive predictive model that enhances diagnostic accuracy which potentially reduces unnecessary procedures.